Safety device for trailers



Aug. 7, 1945.- c. F. MOONEY SAFETY DEVICE FOR TRAILERS Filed April 24, 1944 2 Sheets-Sheet 1 c. MQONEY 1 2,381,305

- SAFETY fiEVIcE FbR TRAILERS Aug. 7, 1945.

Filed April 24, 1944 2 Shegts-Sheet 2 'ness;

Patented Aug. 7, 1 945 UNITE-D sTAT Es PATENT o FicE SAFETY DEVICE non TRAILERS Charles F. Mooney, Charlotte, N. 0., mine: of

one-half to John D. Kluttz, Charlotte, N.,-C.

Application April 24, 1944, Serial No. 532,413 I 6 Claims. (Cl. 280-334) a This invention relates to a safety device for the connection between a tractor and a trailer or a semi-trailer. A semi-trailer has rear wheels which contact the ground and has suitable supporting means such as retractable wheels or other .props to be let down to hold the front end of the trailer in elevated position when it is disconnected from the tractorl The tractor has what is called a fifth wheel, and the trailer has a downwardly projecting pin which is adapted to slide intoa slot in the fifth wheel and be automatically locked in position when the tractor is backed underneath the front end of the trailers It often happens that the tractor-is backed in with too much force and a rebound occurs which results in the connecting pin on the trailer not being properly locked in the fifth wheel rnecha-v nism and'when the tractor starts moving forwardly, the trailer is not pulled by the tractor and the trailer slides off of the iifthwheel as the tractor is pulled from beneath the trailer resulting in the front end of the trailer, which is usually heavily loaded, falling onto'the ground or pavement and doing material and substarbtial damage to the trailer. It 'is an object of this invention to provide safety means which will prevent the front end' of the trailer from disengaging itself from the fifth wheel when failure of the locking mecha-.

nism occurs by providing a latch which is no.1-

showing a portion of the latch-casing broken away; 7

Figure 4 is a view similar to Figure l, but showing the latching mechanism mounted on the exterior of the semi-trailer;

Figure 5 is a top plan view withparts in section of the right-hand portion of Figure 4;

Figure 6 is an isometric view looking at the front end of the semi-trailer and showing portions thereof broken away.

Referring more specifically to the drawings, the numeral It indicates the rear portion of a tractor which on each side thereof usually has a pair wof rails ll having a flange portion l2, rails H being disposed on each side of the framework of the tractor, and each of the rails is secured to the framework of the trailer by any suitable means such as bolts l3.

Bolted on the rails l I and spanning the distance therebetween'by any suitable means such as bolts 14 is a casting l5 having a transversely disposed shaft l6 mounted therein, and this shaft I6 is pivotally mounted at each of its ends in the members l5.

Fixedly secured on the shaft I6 is a fifth wheel member I! which has a flat upper surface l8 and has a slot l9 therein which is divergent as at at its rear end for receiving the coupling pin 23 secured to and projecting downwardly mally disposed in a downward position in front been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, inwhich Figure 1 is a side elevation of a portionof the rear end of a tractor and a portion of the -.front end of a semi-trailer showing the fifth wheel and the connection between the semi-trailer and the tractor;

Figure 2 is a top plan view of the apparatus shown in Figure 1, and omitting the bottom or floor portion of the semi-trailer for sake of clear- Figure 3 is an enlarged detail view look ing from the lower sideof the right-hand corner of Figure 2, and omitting the portions of the trailer to which the apparatus is attached, and

50 disposed in front of the member l1 and will mounted thereina latchor plunger 28, and onefrom the semi-trailer 24.

The semi-trailer 24 is of conventional structure and in oneform, as shown in Figure 2, has a transverse member 25. This transverse member' 25 has a suitable hole cut therein in which a casing- 26 is welded. Casing 26 has slidably side of the casing has a' vertically disposed slot 29 therein through which projects a pin 3|.

Surrounding the pin 3| is a slotted member 32 which isflxedly secured at one end to a rod 33 which is rotatably mounted as at 34 on the front side of the casing 26 and is also rotatably mounted in a suitable upstanding member 35 and has a crank thereon. If desired, a tension spring 31 can be secured to this crankand to the member 35 to hold the latch normally in downward position.

This insures that unless the crank 36 is seized by an operator and the shaft 33 rotated to raise the latch 28, that the latch 28 will always be prevent disengagement of the pin 23 from the fifth wheel member l'l even though, the automatic locking mechanism, not shown, fails to lock the pin 23 in positions through which the plunger 4| projects so that it will be in front of the fifth wheel member i'l.

Casing a has a slot 42 therein, and a laterally projecting pin 43 similar to pin 3| projects through the slot 42 and then the pin 43 projects through a slot 45 in a crank arm 48 which is integral with rod 41 rotatablymounted as at at one end on the exterior of the casing a and having an intermediate portion thereof, rotatably mounted in an upstanding lug 50.

Rod 41 has a crank thereon, and a tension spring 52 is connected thereto at one end, and the other end is connected to the front wall 53 of the semi-trailer. Y

It is thus seen that in both forms of the invention, there is a latch 4| disposed down in the path of travel of the trailer body, and will prevent the trailer from moving rearwardly of the fifth wheel when it fails to become locked in the fifth wheel mechanism. When it is desired to disconnect the trailer and tractor, an operator manually raises the latch by seizing the crank 38 or ii and raises the latch out of the path of the fifth wheel.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims,

, I claim: j

1. In a tractor and trailer, the tractor having a fifth wheel on which the front end of a trailer is adapted to rest, a downwardly projecting latch mounted on the front portion of the trailer and having its lower end normally occupying a position in front of the fifth wheel of the trailer when the tractor and trailer are coupled together to prevent disengagement of the trailer from the fifth wheel and means for moving the latch upwardly to remove the lower end thereof from in front of the fifth wheel. V

2. In a tractor having a fifth wheel on the rear end thereof and provided with means for receiving, a downwardly projecting pin mounted on the front end of a trailer, a downwardly projecting latch mounted on the trailer and whose lower end is normally disposed in front of the fifth wheel when the tractor and trailer are coupled together to prevent the tractor and its fifth iwheel being pulled from beneath the front end of the trailer, and means for moving the lower end of the latch In Figures 4, 5, and 6, a slightly modified form wheel when the fifth wheel moves forwardly relative to the trailer. I

3. In a tractor and trailer combination. the tractor being equipped with a fifth wheel having a rearwardly opening slot therein into which a downwardly projecting pin on the trailer is adapted to move when the tractor is backed beneath the trailer, and a downwardly projecting latch mounted on the trailer and adapted to project downwardly in front of the fifth wheel when the tractor and trailer are coupled together to prevent movement of the fifth wheel forwardlv' from beneath the trailer, the front portion of the lower end of the latch being sloped downwardly and rearwardly to allow it to be raised by the fifth wheel when the tractor is backed beneath the trailer, and means for normally urging the latch downwardly to a position in front of the front'edge of the fifth wheel.

4. In a tractor and trailer, the tractor having afifth wheel and the trailer having a downwardly projecting pin adapted to fit into the fifth wheel, a downwardly projecting latch mounted on the front portion of the trailer and normally occupying a position in front of the fifth wheel of the trailer to prevent disengagement of the trailer from the fifth wheel, the lower end of the latch being sloped downwardly and rearwardly to'cause it to ride onto the upper surface of the fifth wheel when the tractor is backed beneath the front end of the trailer.

5. In a tractor having a fifth wheel on the rear end thereof, a downwardly projecting latch mounted on the trailer and whose lower end is lower end of the latch being sloped downwardly and rearwardly to cause it to ride onto the upper surface of the fifth wheel and occupy a position in front of the fifth wheel when the tractor is backed beneath the front end of the trailer.

6. In a tractor having a fifth wheel on the rear end thereof, provided with means for receiving a downwardly projecting latch mounted on the trailer and whose lower end is normally disposed in front of the fifth wheel when the tractor and trailer are coupled together to prevent the tractor and its fifth wheel being pulled from beneath the front end of the trailer, manually operated means connected to the latch for raising the same upupwardly out of the path traveled by the fifth wardly out of the path of the fifth wheel when it is desired to disconnect the tractor and trailer,

the lower end of the latch being sloped downwardly and rearwardly to cause it to ride onto the upper surface of the fifth wheel when the tractor is backed beneath the front end of the trailer./

I CHARLES F. MOONEY 

